1. Field of the Invention
The present invention relates to an apparatus and method for analyzing contaminants on a wafer surface, and more particularly, to an apparatus and method capable of collecting a sample of contaminants from a wafer surface and analyzing the contaminants.
2. Description of the Related Art
In recent times, high integration and compact size of a semiconductor device have been causing increased adsorption of various contaminants, especially metal contaminants generated from a semiconductor manufacturing line and during a semiconductor manufacturing process onto a wafer surface, adversely affecting performance and yield of the semiconductor device.
Therefore, a process of analyzing contaminants on a wafer surface has become essential in the manufacture of a semiconductor device.
In conventional art, analysis of contaminants has been performed by selecting a predetermined wafer between semiconductor manufacturing lines or semiconductor manufacturing processes, scanning a surface of the selected wafer using a scanning solution such as hydrogen fluoride (HF) to collect a sample for analyzing contaminants from the wafer surface, and analyzing the collected sample through a destructive analysis method using methods such as an atomic absorption spectroscopy, inductively coupled plasma mass spectroscopy (ICP-MS) etc., or a nondestructive analysis method using a total X-ray fluorescent analyzer.
However, while these methods are appropriate to analyze contaminants on a wafer surface, since it is time-consuming to collect a sample for analyzing contaminants, the entire process may be delayed. Therefore, methods of using a laser have been proposed in order to more rapidly analyze contaminants.
For example, Korean Patent Registration No. 244922, entitled “Method of Analyzing Metal Alloy as Metal Target in Semiconductor Process,” registered on Nov. 24, 1999, discloses a method of analyzing contaminants contained in a metal alloy used as a metal target in a sputtering process among semiconductor processes, which may also be applied to a method of analyzing contaminants on a wafer.
Specifically, the contaminant analysis method disclosed in the above patent includes a sample cutting step of cutting a portion of a metal alloy, a surface treatment step of grinding and polishing a surface of the cut sample, a step of sputtering the surface treated sample using a laser ablation device integrated with a mass analyzer, and a step of detecting desired metal elements among metal elements separated during the sputtering step. As a result, it is possible to irradiate a laser to the cut and surface treated sample, extract a specimen for analyzing contaminants from the sample, and rapidly analyzing contaminants of the metal alloy from the extracted specimen.
A method of analyzing contaminants on a wafer adapting the impurity analysis method includes making a sample by cutting a portion of a wafer to be analyzed, moving the sample to a predetermined sealed space to irradiate a laser to the sample, and analyzing a specimen extracted from the sample to analyze contaminants on the wafer. Eventually, in the case of the conventional wafer contaminant analysis method, it is possible to irradiate the laser to the cut sample, extract contaminants from the sample of the specimen, and rapidly analyze contaminants on the wafer from the extracted sample of the specimen.
However, since the method analyzes contaminants from the sample after making the sample for analyzing contaminants on a wafer, sample making time is an additional necessity.
In addition, since the method makes the specimen by cutting the portion of the wafer before analyzing contamination of thie wafer, additional contamination may be generated during the process. That is, according to the conventional wafer contaminant analysis method, since additional contamination may be generated during the process of cutting the portion of the wafer to make the sample, data finally detected and analyzed from may be different from actual contamination of the wafer.